Just out of curiousity, I entered Critque La Grande Jatte in Google.....
The reclining gentleman is a rower/boatman.
>> The distancing quality of Seurat's novel technique made it a fine
vehicle for his dry wit, evident in the occasional visual pun—note the
wafts of cigar smoke that morph into a white dog—as well as in
remarkable gallery of contemporary social types, from the brooding
rower reclining at the lower left to the gawky standing man playing a
French horn in the middle distance. But the pervasive self-absorption
of the figures seems at odds with the integrative harmonies of the
composition as a whole. The painting is rich in such enigmatic
tensions, which are perhaps the secret of its enduring fascination.